Queen Elizabeth II on Wednesday said she never aspired to overtaking her great-great-grandmother Queen Victoria to become Britain's longest-reigning monarch in a brief comment on the historic moment.
As she inaugurated a new railway in Scotland, Elizabeth II said that many people "have also kindly noted another significance attaching to today, although it is not one to which I have ever aspired".
"Inevitably, a long life can pass by many milestones. My own is no exception. But I thank you all and the many others at home and overseas for your touching messages," the 89-year-old monarch said.
Dressed in a turquoise and blue coat and matching hat, the queen was speaking at a ceremony in Tweedbank after boarding a steam train to inaugurate the rail line from the Scottish capital Edinburgh.
Children cheered and waved Scottish and British flags at the event as a group of royal archers stood guard and Scottish First Minister Nicola Sturgeon congratulated the queen.
Royal officials have stressed that the queen wanted to keep the date low-key as the calculation of the length of her reign is based on the moment it began with the death of her father George VI in 1952.